A gas turbine engine generally includes, in serial flow communication, a gas generator compressor, a combustor, a gas generator turbine, and a power turbine. The combustor generates combustion gases that are channeled in succession to the gas generator turbine where they are expanded to drive the gas generator turbine. Then, the combustion gases are channeled to the power turbine where they are further expanded to drive the power turbine. The gas generator turbine is coupled to the gas generator compressor via a gas generator shaft, and the power turbine is coupled to an output shaft via a power turbine shaft. The output shaft may be coupled to a load, such as main rotor blades of a helicopter.
The gas generator compressor typically includes one or more arrays of circumferentially spaced airfoils. In certain engines, the one or more arrays of airfoils are actuated through the operation of a controllable airfoil or vane actuator. More specifically, in some engines, a first array of airfoils is actuated through the operation of a first actuator, and a second array of airfoils is actuated through the operation of a separate, second actuator. During operation, the first and second actuators adjust the angular position of the first and second array of airfoils, respectively, based on a monitored operating parameter (e.g., core speed) of the gas turbine engine. However, since the first and second actuators operate independently of one another, the position control loops for controlling the operation of the two actuators are not synchronized, which leads to unintended mismatches between the first and second arrays of airfoils.
Accordingly, a system and method for synchronizing the operation of actuators used to adjust the angular position of airfoils (e.g., vanes) of a gas turbine engine would be welcomed in the technology.